INVESTIGATIONS ON SCIAPHILA WAHLBOMIANA, ETC. 57 



3Iinusc2ilana, I find there is no hook at all at the hinder 

 margin of the upper flap, but it ends with a straightlj cut, 

 clean margin. Probably this occurrence is only accidental 

 and the hook may have got turned down beneath the upper 

 genital flap. 



In Sc. Wahlbomiana the upper genital flap has a more 

 triangular form, which terminates in a stout, horny hook, 

 which is curved downwards; hence there is almost nothing 

 to be seen of a hinder margin to the flap with protruding 

 corners. The upper surface of the flap shows two hemi- 

 spherical prominences, which are separated by a furrow in 

 the medial line. The entire form appears more compact 

 than in Minusculana and is of a darker brown colour. In 

 the lateral flaps I do not perceive any difference. 



I must here again call attention to the fact that these 

 differences in the form of the middle, upper, genital flap are 

 not constant throughout, since there are plenty of inter- 

 mediate forms between the more quadrangular shape we 

 find in Minusculana and the more triangular form in Wahl- 

 bomiana. The typical Walilbomiana and the var. commu- 

 nana have especially the more triangular form, whereas the 

 var. virgaureana and the var. alticolana have again a more 

 quadrangular form. The var. derivana^ Lah. {paraliajia), 

 differs somewhat, as already noticed, in the form of the 

 middle genital flap of the male; it is indeed also quadrangular, 

 but extraordinarily large, and forms at the base two blunt 

 knobs projecting upwards, whilst the terminal half is level 

 above. The corners of the hinder margin are prominent, 

 but rounded, the hook in the middle shorter, but thicker and 

 more strongly curved downwards. That these differences 

 would justify our placing it as a distinct species, I do not 

 believe, since as we have already seen the form of the middle 



